Vandall Thomas "Van" King was born in Skowhegan, Maine on September 12, 1948, the son of Doris M. and Ronald L. King, a house painter. He grew up in Slowhegan and began collecting minerals at age 9, inspired by his uncle who collected minerals from a construction project, and then from a mine. Van's fifth grade school teacher also collected minerals and was very encouraging. In high school there were mineral collectors on his newspaper route, and they took him to the Dunton quarry in Newry, Maine in 1963. That year he also attended his first mineral shows in New England. After that he hitchhiked his way around Maine and New Hampshire to collect minerals at numerous localities.

Van attended the University of Maine at Orono (1967-1972) and the State University of New York at Buffalo (1976-1980), where he received his M.S. and Ph.D.

At Orono he served as Student Mineralogy Curator (1970), then worked as a photographer at WMEB-TV (1971-1972), and conducted Environmental Science Surveys at Colby College and the University of Maine (1970-1972). Taking a break to earn income for Graduate School, he taught Earth Science at Berlin High School in Berlin, New Hampshire (1972-1973), worked as an Environmental Biologist at the University of Maine (1973-1976), and was Staff Mineralogist for Ward's Natural Science Establishment in Rochester, New York (1979-1987)—his first experience in mineral dealing; since 1987 he has been a Consulting Mineralogist for Ward's. In addition to he mineralogical work, he has served as a grant writer and project supervisor for various outreach health care services (Fetal Alcohol Spectrum Disorders, Early Youth Substance Use, Dual Diagnosis Health Issues, Juvenile rehabilitation, AIDS Outreach, Prisoner Transition into the Community, Homelessness) at Unity Health Hospital in Rochester (2000-2004).

His consulting activities currently include book publishing and editing services in addition to technical writing, curatorial assistance, photography, geological evaluations, and mineral collection appraisals. Van specializes in systematic and regional mineralogy, and his personal bibliography currently lists 240 articles and 16 books, including co-authorship of Dana's New Mineralogy (1997). He was a contributing editor for Minerals and Their Localities (2004), and outside reader and contributing editor to volumes 4 and 5 of Handbook of Mineralogy. He has edited scientific articles for American Mineralogist and Canadian Mineralogist, and has acted as a outside editor for Rocks and Minerals and Matrix. And he was editor and publisher Geoliterary Journal for four years. He has served as a management-level editor for Mindat since 2008, and is co-founder of the Systematic Mineral Dealers Association and the Geoliterary Society. He has also presented over 350 mineralogical lectures in 22 states and three countries.

Van was the Maine State Chemistry Science Fair Champion (“Qualitative Analysis as a Mineralogical Tool”) in 1966. He was elected a Fellow of the Rochester Academy of Science in 1985, received the Eastern Federation of Mineral and Lapidary Society teaching excellence award in 1993, the Wild Acres Workshop teaching excellence award in 1993, and the American Federation of Mineral and Lapidary Societies Public Service Award 1994.

Van attended his first Tucson show in 1980 (representing Ward's), and has also followed most of the important mineral shows throughout the U.S. and eastern Canada, as well as the shows in Sainte-Marie-aux-Mines and Paris, France and Oxford, England. Van's personal collection has from the beginning been a systematic mineral collection and he actively traded through the mail as a teenager. He became a micromounter at the age of 15 and now has about 25,000 micromounts plus about 10,000 drawer and display specimens including more than a dozen that qualify as the best known examples of their species. Over the years he has also sold portions of his collection to raise money for various purposes. He sold a suite of 250 Långban, Sweden specimens including one of the world's best trimmerites plus over 200 other species in 1992; he sold his Congo uranium mineral suite, including one of the world's best becquerelites, to Excalibur Minerals in 2004; he sold a comprehensive suite of tellurium minerals containing the world's best spiroffite and one of the world's best denningites, as well as a fine mroseite from Moctezuma (2005); he also sold a Franklin, New Jersey micromount collection containing the world's best hauckite, flinkite, and other rarities in 2006, and various Maine minerals have been sold since 2006 to benefit of the Maine Mineral Museum in Bethel, Maine.

Still an active field collector, Van manages to get out into the field about 15-20 times a year. He likes to collect in granite pegmatite areas in Maine, New Hampshire, Massachusetts, Connecticut, North Carolina, South Dakota, and San Diego County, California, and has collected widely in Ontario, Quebec, and Nova Scotia, Canada. Although he is primarily a consultant, he was associated with the late Belgian mineral dealer Gilbert Gauthier for over 20 years as his assistant at the Detroit, Franklin, Rochester, Denver, Pasadena, and Tucson mineral shows as well as one show in Sainte Marie-aux-Mines and one show in Paris. He has also worked for various other dealers on an occasional basis, but has never had a store-front business. While a buyer for Ward's he purchased a large portion of the Carlton Davis Collection and the Clifford Vickery (Ontario, Canada) Educational Minerals inventory. The most famous collection he placed was the Robert Hesse mineral collection of Philadelphia; the dealer of record was Richard Hauck. He also purchased and distributed the Alice and Fred Kraissl micromount collection. As a consultant he has had occasion to help distribute various other mineral collections and was the only sales agent for the Curt Segeler mineral collection. He has also sold antiquarian mineralogical books by mail-order and has cataloged four of the most important mineralogical/geological personal libraries in the U.S.

All of Van's mineral collection labels list his address simply as Rochester, New York and were first printed in 1985 on orange stock. Blue and yellow labels were introduced in 1994. The colors originally were intended for different purposes, but in practice no distinction was ever made in their use. A small-sized micromount label which fits inside a micromount cover was also produced around 1996.